With the development of wireless communication network technology, wireless communication networks have been established in most countries around the world and are used to provide wireless communication services.
In recent years, the number of opportunities for people to communicate with each other irrespective of where they are located, such as a local area, a country, and so forth, has been increasing. This causes an increase in the number of international calls.
A roaming service refers to a service that lends another communication service provider's network and provides a communication service to a portable terminal user when the portable terminal is moved from one communication service provider's area to another. That is, the roaming service allows the portable terminal user to enjoy a communication service irrespective of where he/she is located.
Portable terminal users that subscribe to wireless communication services store user information including other users' contact information in their portable terminals, such that they can subsequently search for corresponding contact information or contact a called user corresponding to the information. In conventional technology, the user information is configured to contain simple information, for example, a name, a phonebook, and such. When a user searches for another user's name from his/her portable terminal, the portable terminal displays another user's phone number.
Therefore, a system is required to efficiently provide a variety of user information, based on local areas and countries where users are located and their movement.